BOUGAINVILLIA SUPERCILIARIS. 153 



Gulf of Georgia, and was also found in the harbor of San Francisco 

 during May and November. 



Behring's Strait (Brandt) ; Gulf of Georgia, W. T. (A. Agassiz). 



Cat. No. 33, San Francisco, Cal., March, 1859, A. Agassiz. Hydrarium. 



Cat. No. 49, Gulf of Georgia, W. T., May, 1859, A. Agassiz. Medusa. 



Bougainvillia superciliaris AGASS. 



Bougainvillia superciliaris AGASS. Cont. Nat. Hist. U. S., IV. pp. 289, 291, Figs. 37 -39 ; p. 344, 



PI. 27, Figs. 1-7. 1862. 



Hippocrene superciliaris AGASS. ; in Mem. Am. Acad., IV. p. 250, Pis. 1-3. 

 Hi/ipocrejie superciliaris STIMPS. Mar. Inv. Grand Manan, p. 11. 1853. 

 Bouyaindllia superciliaris A. AGASS. ; in Proc. Bost. Soc. Nat. Hist., IX. Figs. 24, 25. 

 Hippocrene Bougainvillei GOULD (nee Br., nee Less.). Rep. Inv. Mass., p. 348. 1841. 

 ? Tubularia ramosa GOULD. Rep. Inv. Mass., p. 350. 1841. 

 ? Eudendrium cingulatum STIMPS. Mar. Inv. Grand Manan, p. 9. 1853. 



The development of the young Medusae of the species, formerly re- 

 ferred to Bougainvillia, shows beyond doubt that the genera Bougain- 

 villia and Margelis are founded upon structural differences ; from the 

 earliest stages we can trace the peculiar short and long digestive cavities 

 so characteristic of these two genera, as well as the differences in the 

 form of the bell. BougainmUia superciliaris (Fig. 232), of which a 



Fig. 232. 



complete description has already been given by Professor Agassiz, in 

 the Memoirs of the American Academy for 1849, is one of our most 

 common Medusae, but readily escapes notice on account of its small size. 

 The Hydrarium (Fig. 233) has also been figured by Professor Agassiz in 

 Vol. IV. of his Contributions, but the development has not been traced 

 before. The Medusa buds are found along the stem below the heads ; 

 Figs. 234, 235 are early stages, when the bell is elongated, and inca- 



Fig. 232. Magnified profile view of adult Bougainvillia superciliaris. 

 NO. n. 20 



